Mixins: Can you do it Ruby-Style? (Part 1)

Ok, Ruby shows us how to do it:

module TalkMixin
   def say_hello
       puts "hello"
    end
end

class Animal
   def eat
       puts "mpf mpf mpf ..."
    end
end

class Dog < Animal
   include TalkMixin

   def bark
       puts "wuff wuff"
    end
end

dog = Dog.new
dog.eat
dog.bark
dog.say_hello

Now, extension methods in C# allow us to do something similar:

public interface ITalker{}

public static class TalkMixin {
   public static void SayHello(this ITalker animal){
       Console.WriteLine("hello");
   }
}

public class Animal {
   public void Eat() {
       Console.WriteLine("mpf mpf mpf ...");
   }
}

public class Dog : Animal, ITalker {
   public void Bark() {
       Console.WriteLine("wuff wuff");
   }
}

[TestFixture]
public class MixinTest {
   [Test]
   public void Inerface_Mixin() {
       Dog dog = new Dog();
       dog.Eat();
       dog.Bark();
       dog.SayHello();
   }
}

Not bad... this technique is heavily used in .NET 3.5, for instance in the IEnumerable interface.